title: Proteomics analysis of the regulatory role of Rpf/DSF cell-to-cell signaling system in the virulence of Xanthomonas campestris.
abstract: The black rot pathogen Xanthomonas campestris utilizes molecules of the diffusible signal factor (DSF) family as signals to regulate diverse processes contributing to virulence. DSF signal synthesis and transduction requires proteins encoded by the rpf gene cluster. RpfF catalyzes DSF synthesis, whereas the RpfCG two-component system links the perception of DSF to alteration in the level of the second messenger cyclic di-GMP. As this nucleotide can exert a regulatory influence at the post-transcriptional and post-translational levels, we have used comparative proteomics to identify Rpf-regulated processes in X. campestris that may not be revealed by transcriptomics. The abundance of a number of proteins was altered in rpfF, rpfC, or rpfG mutants compared with the wild type. These proteins belonged to several functional categories, including biosynthesis and intermediary metabolism, regulation, oxidative stress or antibiotic resistance, and DNA replication. For many of these proteins, the alteration in abundance was not associated with alteration in transcript level. A directed mutational analysis allowed us to describe a number of new virulence factors among these proteins, including elongation factor P and a putative outer membrane protein, which are both widely conserved in bacteria.
authors.forename: Aileen
authors.initials: A
authors.lastname: O'Connell
authors.forename: Shi-Qi
authors.initials: SQ
authors.lastname: An
authors.forename: Yvonne
authors.initials: Y
authors.lastname: McCarthy
authors.forename: Fabian
authors.initials: F
authors.lastname: Schulte
authors.forename: Karsten
authors.initials: K
authors.lastname: Niehaus
authors.forename: Yong-Qiang
authors.initials: YQ
authors.lastname: He
authors.forename: Ji-Liang
authors.initials: JL
authors.lastname: Tang
authors.forename: Robert P
authors.initials: RP
authors.lastname: Ryan
authors.forename: J Maxwell
authors.initials: JM
authors.lastname: Dow
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D002450:Cell Communication; D004252:DNA Mutational Analysis; D015180:Electrophoresis, Gel, Two-Dimensional; D015964:Gene Expression Regulation, Bacterial; D017930:Genes, Reporter; D009154:Mutation; D010935:Plant Diseases / Q000382:microbiology*; D018515:Plant Leaves / Q000382:microbiology; D040901:Proteomics; D012329:RNA, Bacterial / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics; D031224:Raphanus / Q000382:microbiology*; D011993:Recombinant Fusion Proteins; D015398:Signal Transduction; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D014774:Virulence; D037521:Virulence Factors / Q000235:genetics / Q000378:metabolism; D016959:Xanthomonas campestris / Q000235:genetics / Q000378:metabolism* / Q000472:pathogenicity / Q000502:physiology
chemical_list: D001426:Bacterial Proteins; D012329:RNA, Bacterial; D012333:RNA, Messenger; D011993:Recombinant Fusion Proteins; C419552:RpfG protein, Xanthomonas campestris; D037521:Virulence Factors; C102500:rpfC protein, Xanthomonas